<template>
  <div>
    <div class="center">
      <div class="item"></div>
    </div>
    <div class="start">
      <div class="item"></div>
    </div>
    <div class="end">
      <div class="item"></div>
    </div>
  </div>
</template>
<style scoped>
.center {
  display: flex;
  flex-direction: column;
  /* justify-content: center; */
  align-items: center;
  height: 120px;
}
.start {
  display: flex;
  justify-content: flex-start;
}
.end {
  display: flex;
  justify-content: flex-end;
}
.item {
  background: red;
  height: 100px;
  width: 100px;
  border: 1px solid #000;
}
</style>